Previously known processes for producing butadiene from butene rich hydrocarbonaceous feeds have used reactors whose shapes were largely governed by pressure drop considerations leading to reactors that would be considered shallow—the bed depth (linear dimension in the direction of flow) of all four layers of the bed often being limited to about a meter or less with the total height of the oxidative dehydrogenation catalyst being only about 55-60 cm (22-24 inches) or less. In particular, previous processes typically used natural gas to vaporize butene and heat a mixture of hydrocarbons, preferably butenes, oxygen and steam to a temperature in excess of 260° C. (500° F.), more commonly in excess of about 315° C. (600° F.), and preferably over about 345° C. (650° F.) or, in some cases, even over 370° C. (700° F.). In a typical process, the reaction mixture includes butenes, oxygen in an amount of from about 0.4 moles to about 0.8 moles, more typically from slightly in excess of 0.5 moles up to about 0.65 moles of oxygen for each mole of butene in the butene rich hydrocarbonaceous feed, and superheated steam in amounts of from about 12:1 to about 16:1. The heated reaction mixture was passed over a multilayer bed comprising four layers: an inert flow distribution and catalyst retention layer which restricted channeling of the reaction mixture as it passed through the catalyst bed and also served to hold the lower layers in place against vorticity that might be present above the catalyst bed; the second layer comprising the bulk of the bed was an oxidation/dehydrogenation catalyst; while the third layer comprises an aldehyde and alkyne removal (“AAR”) catalyst which converts alkynes and aldehydes in the product into compounds which are less detrimental to processes for polymerization of butadienes than alkynes and aldehydes. The lowest layer comprises an inert particulate support material. As mentioned typically, the total bed height would be limited to about a meter or less while the depth of the oxidative dehydrogenation layer was limited to less than about 56 cm (22 inches).
While passing over the oxidation/dehydrogenation catalyst, the butenes were converted to butadiene accompanied by the liberation of a great deal of heat, resulting in temperatures in the neighborhood of 540° C. or 595° C. (1000° F. or 1100° F.). In the past, when the depth of the catalyst bed was shallow, breakthrough of oxygen to the AAR catalyst could be difficult to prevent even though care might typically be exercised to ensure that all of the oxygen present in the reaction mixture was consumed before reaching the AAR catalyst. Oxygen breakthrough can lead to both loss of the desired butadiene product and, even more seriously, damage to the AAR catalyst and/or reactor vessel. Consequently, in many cases, these considerations led to use of rather conservative cycle length and premature catalyst changeout, so that the effective catalyst life was shorter than necessary and percentage of time on-stream suffered.
Subsequent to reaction, the reaction product mixture is cooled and butadiene separated by contact with absorber oil and subsequent fractionation. Typically, these processes produce crude butadiene at a purity ranging from about 50 to about 70%, more typically from about 55 to about 65%, which is passed onward in the plant for further processing using known technologies.
References of interest are discussed below.
Lewis; HYDROCARBON CONVERSION PROCESS USING NOVEL METALLO MANGANESE OXIDES; U.S. Pat. No. 5,772,898; Jun. 30, 1998; relates to a hydrocarbon conversion process comprising contacting a hydrocarbon feed with a catalyst comprising a crystalline metallo manganese oxide composition having a three-dimensional framework structure, an intracrystalline pore system and an empirical chemical composition on an anhydrous basis expressed by the formula:AyMn8-xMxO16 where A is a templating agent selected from alkali metals, alkaline earth metals and ammonium ion, “y” is the moles of A and varies from the group consisting of about 0.5 to about 2.0, M is a metal selected from the group consisting of chromium, zirconium, tin, platinum, rhodium, niobium, tantalum, vanadium, antimony, ruthenium, gallium and germanium, “x” is the moles of M and varies from about 0.01 to about 4.0 and is characterized in that manganese has a valence of +3, or +4, M has a valence of +3, +4 or +5 and the composition has the hollandite structure.
Sasaki et al.; IRON-ANTIMONY-CONTAINING METAL OXIDE CATALYST COMPOSITION AND PROCESS FOR PRODUCING THE SAME; U.S. Pat. No. 5,139,988; Aug. 18, 1992; relates to a composition which contains as essential components: crystalline iron antimonate and at least one element selected from the group consisting of vanadium, molybdenum, and tungsten; is useful as a catalyst in the oxidation reaction of organic compounds. Also, a process for producing the composition is disclosed.
Dejaifve et al.; CATALYST FOR DEHYDROGENATING ORGANIC COMPOUNDS, A PROCESS FOR ITS PREPARATION AND ITS USE; U.S. Pat. No. 4,975,407; Dec. 4, 1990; relates to a catalyst derived from iron oxides providing agents and potassium oxide providing agents, characterized in that the molar ratio is in the range of from 1.5 to 60 and that a potassium ferrite K2Fe12O19 phase is present supported on an octahedral Fe3O4 matrix, showing crystalline epitaxy between the hexagonal structure of K2Fe12O19 and the (111) planes of the Fe3O4 spinel structure.
McFarland, ACETYLENE REMOVAL PROCESS; U.S. Pat. No. 4,658,080; Apr. 14, 1987 relates to a process for removing acetylene from organics streams, particularly those streams resulting from oxidative-dehydrogenation of C4-C8 hydrocarbons, using an acetylene reduction catalyst comprising ferrite and nickel oxide, an alkaline earth metal oxide, carbonate or hydroxide of magnesium, calcium, strontium or barium and an alkaline metal oxide carbonate or hydroxide based on lithium, potassium, sodium, or rubidium. Use of the catalyst is exemplified in a pipe reactor in which oxidative dehydrogenation is conducted on C4-C8 hydrocarbons and the reaction product is immediately passed over a bed of the acetylene reduction catalyst in the same pipe reactor. See also McFarland; ACETYLENE REMOVAL PROCESS; U.S. Pat. No. 4,644,088; Feb. 17, 1987 and U.S. Pat. No. 4,513,159; Apr. 23, 1985.
Patel; PROCESS FOR REMOVING A-ACETYLENES FROM DIOLEFINS; U.S. Pat. No. 4,266,086; relates to removal of alpha-acetylenes including vinyl acetylene and methyl acetylene from a feedstream containing butadiene and mixed monoolefins and alkanes contaminated with alpha-acetylenes in an amount up to about 1.0 percent by weight (% by wt) by contacting the liquid phase with a supported metal oxide catalyst (cupric oxide, silver oxide, or mixtures thereof) in the absence of hydrogen, at a temperature in the range from about 90° C. (200° F.) to about 130° C. (260° F.).
In Besozzi et al.; PURIFICATION OF UNSATURATED COMPOUNDS; U.S. Pat. No. 4,150,063; Apr. 17, 1979; gaseous streams containing unsaturated hydrocarbons and carbonyl compounds are contacted with a catalyst comprising at least one metal of group 8, 1b, 2b, 4b, 6b and at least one element from group 1a and 2a to destroy the carbonyl compounds without substantial loss of unsaturated hydrocarbons.
Miklas, METHOD OF ACTIVATING ZINC-FERRITE OXIDATIVE DEHYDROGENATION CATALYST; U.S. Pat. No. 3,953,370; Apr. 27, 1976 relates to use of steam at a temperature of from 370-700° C. (700-1300° F.) to activate a zinc ferrite oxidative hydrogenation catalyst for preparation of butadiene from C4-C8 hydrocarbons.
Tschopp; DIOLEFIN PRODUCTION AND PURIFICATION; U.S. Pat. No. 3,943,185; Mar. 9, 1976 relates to a process for producing a stream of oxidatively dehydrogenated C4 hydrocarbons substantially free of oxygen and inert noncondensable gases removed comprising absorbing the C4 hydrocarbons in an absorber oil in a first zone; stripping oxygen and inert noncondensable gases from the mixture of adsorber oil and C4 hydrocarbons in a second zone which is operated under conditions of temperature and pressure to maintain an aqueous phase in the second zone; and withdrawing (1) a predominately aqueous phase from the second zone, (2) an overhead of predominately all of the oxygen and inert noncondensable gases and a bottoms of adsorber oil and C4 hydrocarbon substantially free of oxygen and inert noncondensable gases.
In Woerner et al; PURIFICATION OF UNSATURATED HYDROCARBONS BY EXTRACTIVE DISTILLATION WITH ADDITION OF LIQUID SOLVENT TO STRIPPER OVERHEAD; U.S. Pat. No. 3,496,070; Feb. 17, 1970, a hydrocarbon separation process is provided for the separation of a hydrocarbon mixture comprising 4 to 5 carbon atoms including unsaturated hydrocarbons which comprises: extractively distilling the hydrocarbon mixture with a selective solvent in an extractive distillation column whereby hydrocarbon is selectively extracted in the extractive distillation column to form a hydrocarbon-rich solvent fraction which is fed to a solvent stripping column with said solvent being taken off as a bottoms from said stripping column and a vaporous hydrocarbon fraction being taken as an overhead fraction from said stripping column; adding said selective solvent in liquid phase to the vaporous overhead from the solvent stripper to lower the pressure in the overhead condenser of the solvent stripper column and in the solvent stripper. It is said that the product of the process may alternatively be taken as an overhead from the solvent stripper instead of from the extractive distillation column.
Bajars; DEHYDROGENATION WITH MAGNESIUM FERRITE; U.S. Pat. No. 3,284,536; Nov. 8, 1966 relates to dehydrogenating hydrocarbons in the vapor phase at elevated temperatures in the presence of oxygen and a catalyst containing magnesium ferrite. Hydrocarbons to be dehydrogenated according to the process are hydrocarbons of 4 to 7 carbon atoms, preferably aliphatic hydrocarbons selected from the group consisting of saturated hydrocarbons, monoolefins, diolefins and mixtures thereof of 4 to 5 or 6 carbon atoms having a straight chain of at least four carbon atoms, and cycloaliphatic hydrocarbons. Oxygen is present in the reaction zone in an amount within the range of 0.2 to 2.5 mols of oxygen per mol of hydrocarbon to be dehydrogenated. The temperature for the dehydrogenation reaction will be greater than 250° C., such as greater than about 300° C. or 375° C., and the maximum temperature in the reactor may be about 650° C. or 750° C. or perhaps higher under certain circumstances.
Levin et al.; PROCESS FOR REMOVING ALDEHYDES AND/OR KETONES FROM AN OLEFINIC STREAM; US Patent Application Publication 2004/0122275; Jun. 24, 2004 relates to removing an oxygenate impurity selected from aldehyde and/or ketone, from an olefinic product stream. The product stream is contacted with a metal oxide-containing catalyst in the presence of a C1 to C6 alcohol under conditions sufficient to convert the oxygenate impurity to an olefin and/or oxygenate of higher carbon number than the aldehyde and/or ketone. The metal oxide-containing catalyst typically comprises an oxide of at least one metal selected from the group consisting of Group 2 metals, Group 3 metals (including Lanthanide and Actinide series metals), and Group 4 metals. The catalyst may include two or more metals from the same group of metals. In one embodiment, the metal oxide containing catalyst comprises lanthanum oxide and magnesium oxide. In another, the catalyst comprises an oxide of a metal selected from the group consisting of Ti, Zr, and Hf. In yet another embodiment, the catalyst preferably comprises an oxide of a metal selected from the group consisting of Sc, Y, La, and Ce.
Van Egmond; DISTILLATION PROCESS FOR REMOVAL OF METHYL ACETYLENE AND/OR PROPADIENE FROM AN OLEFIN STREAM; US Patent Application Publication 2004/0122268; Jun. 24, 2004 relates to a process for producing a propylene product stream and/or a butylene product stream from an olefin stream by removing Methyl acetylene and/or propadiene (MAPD) from the propylene and/or butylene in a two-step fractionation process.
Welch, et al. in “BUTADIENE VIA OXIDATIVE DEHYDROGENATION”, Hydrocarbon Processing November 1978 pp. 131-136; discuss an oxidative dehydrogenation process, in which steam, air or oxygen, and normal butenes are heated and passed over an undisclosed autoregenerative heterogeneous catalyst at around 430° C. (800° F.) using steam as a heat sink to moderate the temperature rise in the adiabatic reactor system without using gas phase additives such as halogen and sulfur compounds. The process is said to consume essentially all of the oxygen in the feed usually leaving oxygen levels in the effluent below 0.3 percent. Acetylenes and oxygenated byproducts are major by products.